pv/data/analogsnapshot.cpp

   1 /*
   2  * This file is part of the PulseView project.
   3  *
   4  * Copyright (C) 2012 Joel Holdsworth <joel@airwebreathe.org.uk>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
  19  */
  20
  21 #include <extdef.h>
  22
  23 #include <assert.h>
  24 #include <string.h>
  25 #include <stdlib.h>
  26 #include <math.h>
  27
  28 #include <algorithm>
  29
  30 #include <boost/foreach.hpp>
  31
  32 #include "analogsnapshot.h"
  33
  34 using boost::lock_guard;
  35 using boost::recursive_mutex;
  36 using std::max;
  37 using std::max_element;
  38 using std::min;
  39 using std::min_element;
  40
  41 namespace pv {
  42 namespace data {
  43
  44 const int AnalogSnapshot::EnvelopeScalePower = 4;
  45 const int AnalogSnapshot::EnvelopeScaleFactor = 1 << EnvelopeScalePower;
  46 const float AnalogSnapshot::LogEnvelopeScaleFactor =
  47         logf(EnvelopeScaleFactor);
  48 const uint64_t AnalogSnapshot::EnvelopeDataUnit = 64*1024;      // bytes
  49
  50 AnalogSnapshot::AnalogSnapshot(const uint64_t expected_num_samples) :
  51         Snapshot(sizeof(float))
  52 {
  53         set_capacity(expected_num_samples);
  54
  55         lock_guard<recursive_mutex> lock(_mutex);
  56         memset(_envelope_levels, 0, sizeof(_envelope_levels));
  57 }
  58
  59 AnalogSnapshot::~AnalogSnapshot()
  60 {
  61         lock_guard<recursive_mutex> lock(_mutex);
  62         BOOST_FOREACH(Envelope &e, _envelope_levels)
  63                 free(e.samples);
  64 }
  65
  66 void AnalogSnapshot::append_interleaved_samples(const float *data,
  67         size_t sample_count, size_t stride)
  68 {
  69         assert(_unit_size == sizeof(float));
  70
  71         lock_guard<recursive_mutex> lock(_mutex);
  72
  73         _data = realloc(_data, (_sample_count + sample_count) * sizeof(float));
  74
  75         float *dst = (float*)_data + _sample_count;
  76         const float *dst_end = dst + sample_count;
  77         while (dst != dst_end)
  78         {
  79                 *dst++ = *data;
  80                 data += stride;
  81         }
  82
  83         _sample_count += sample_count;
  84
  85         // Generate the first mip-map from the data
  86         append_payload_to_envelope_levels();
  87 }
  88
  89 const float* AnalogSnapshot::get_samples(
  90         int64_t start_sample, int64_t end_sample) const
  91 {
  92         assert(start_sample >= 0);
  93         assert(start_sample < (int64_t)_sample_count);
  94         assert(end_sample >= 0);
  95         assert(end_sample < (int64_t)_sample_count);
  96         assert(start_sample <= end_sample);
  97
  98         lock_guard<recursive_mutex> lock(_mutex);
  99
 100         float *const data = new float[end_sample - start_sample];
 101         memcpy(data, (float*)_data + start_sample, sizeof(float) *
 102                 (end_sample - start_sample));
 103         return data;
 104 }
 105
 106 void AnalogSnapshot::get_envelope_section(EnvelopeSection &s,
 107         uint64_t start, uint64_t end, float min_length) const
 108 {
 109         assert(end <= get_sample_count());
 110         assert(start <= end);
 111         assert(min_length > 0);
 112
 113         lock_guard<recursive_mutex> lock(_mutex);
 114
 115         const unsigned int min_level = max((int)floorf(logf(min_length) /
 116                 LogEnvelopeScaleFactor) - 1, 0);
 117         const unsigned int scale_power = (min_level + 1) *
 118                 EnvelopeScalePower;
 119         start >>= scale_power;
 120         end >>= scale_power;
 121
 122         s.start = start << scale_power;
 123         s.scale = 1 << scale_power;
 124         s.length = end - start;
 125         s.samples = new EnvelopeSample[s.length];
 126         memcpy(s.samples, _envelope_levels[min_level].samples + start,
 127                 s.length * sizeof(EnvelopeSample));
 128 }
 129
 130 void AnalogSnapshot::reallocate_envelope(Envelope &e)
 131 {
 132         const uint64_t new_data_length = ((e.length + EnvelopeDataUnit - 1) /
 133                 EnvelopeDataUnit) * EnvelopeDataUnit;
 134         if (new_data_length > e.data_length)
 135         {
 136                 e.data_length = new_data_length;
 137                 e.samples = (EnvelopeSample*)realloc(e.samples,
 138                         new_data_length * sizeof(EnvelopeSample));
 139         }
 140 }
 141
 142 void AnalogSnapshot::append_payload_to_envelope_levels()
 143 {
 144         Envelope &e0 = _envelope_levels[0];
 145         uint64_t prev_length;
 146         EnvelopeSample *dest_ptr;
 147
 148         // Expand the data buffer to fit the new samples
 149         prev_length = e0.length;
 150         e0.length = _sample_count / EnvelopeScaleFactor;
 151
 152         // Break off if there are no new samples to compute
 153         if (e0.length == prev_length)
 154                 return;
 155
 156         reallocate_envelope(e0);
 157
 158         dest_ptr = e0.samples + prev_length;
 159
 160         // Iterate through the samples to populate the first level mipmap
 161         const float *const end_src_ptr = (float*)_data +
 162                 e0.length * EnvelopeScaleFactor;
 163         for (const float *src_ptr = (float*)_data +
 164                 prev_length * EnvelopeScaleFactor;
 165                 src_ptr < end_src_ptr; src_ptr += EnvelopeScaleFactor)
 166         {
 167                 const EnvelopeSample sub_sample = {
 168                         *min_element(src_ptr, src_ptr + EnvelopeScaleFactor),
 169                         *max_element(src_ptr, src_ptr + EnvelopeScaleFactor),
 170                 };
 171
 172                 *dest_ptr++ = sub_sample;
 173         }
 174
 175         // Compute higher level mipmaps
 176         for (unsigned int level = 1; level < ScaleStepCount; level++)
 177         {
 178                 Envelope &e = _envelope_levels[level];
 179                 const Envelope &el = _envelope_levels[level-1];
 180
 181                 // Expand the data buffer to fit the new samples
 182                 prev_length = e.length;
 183                 e.length = el.length / EnvelopeScaleFactor;
 184
 185                 // Break off if there are no more samples to computed
 186                 if (e.length == prev_length)
 187                         break;
 188
 189                 reallocate_envelope(e);
 190
 191                 // Subsample the level lower level
 192                 const EnvelopeSample *src_ptr =
 193                         el.samples + prev_length * EnvelopeScaleFactor;
 194                 const EnvelopeSample *const end_dest_ptr = e.samples + e.length;
 195                 for (dest_ptr = e.samples + prev_length;
 196                         dest_ptr < end_dest_ptr; dest_ptr++)
 197                 {
 198                         const EnvelopeSample *const end_src_ptr =
 199                                 src_ptr + EnvelopeScaleFactor;
 200
 201                         EnvelopeSample sub_sample = *src_ptr++;
 202                         while (src_ptr < end_src_ptr)
 203                         {
 204                                 sub_sample.min = min(sub_sample.min, src_ptr->min);
 205                                 sub_sample.max = max(sub_sample.max, src_ptr->max);
 206                                 src_ptr++;
 207                         }
 208
 209                         *dest_ptr = sub_sample;
 210                 }
 211         }
 212 }
 213
 214 } // namespace data
 215 } // namespace pv